Dorice "DeeDee" Moore was a suspect in a missing man's murder, and investigators said she wanted to move the body before they could find it. But how did they find out about her Jan. 24 shopping trip to the Brandon Walmart Supercenter?

Undercover detectives didn't tail her to the store. They weren't watching her every move.

They secretly placed a GPS tracking device onto her vehicle.

The same technologies we use every day — cell phones, social networking, GPS — also are used by law enforcement to investigate, track and arrest criminals. The problem, critics say, is when these technologies are used without oversight — and to erode privacy.

A judge on the 9th U.S. Circuit Court of Appeals recently called out his fellow judges on both counts.

His rebuke came after the court ruled that federal agents could not only plant a GPS tracking device on a vehicle without getting a warrant, but they could go onto private property to do so.

That was too much for Chief Judge Alex Kozinski.

"The needs of law enforcement, to which my colleagues seem inclined to refuse nothing, are quickly making personal privacy a distant memory," he wrote in a widely read dissent.

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The Global Positioning System of satellites in orbit has become ubiquitous in modern life. The private sector uses it to keep tabs on employees. The public uses it to keep from getting lost. Florida uses it to track 2,620 sex offenders.

But how often is it used in criminal investigations?

None of the Tampa Bay area's major law enforcement agencies would discuss the issue. Their investigative techniques are exempt from public records law.

"We do utilize GPS for investigations, and we do have a policy that addresses the usage," wrote Hillsborough sheriff's spokeswoman Debbie Carter in an e-mail. "But we cannot release the policy due to the fact that it reveals investigative techniques."

The Pinellas-Pasco State Attorney's Office would only confirm that it has obtained judicial approval to track suspects using GPS.

Defense attorneys say they're encountering the technology more frequently. But no one can say for sure how often it's used.

"In speaking to law enforcement, I understand that it is being used more and more often in their investigations," said Tampa defense attorney Richard Escobar. "It's an easier way to track individuals than doing mobile surveillance."

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How GPS tracking is used in Florida depends on which agency is using it. Local, state and federal officers follow different rules.

According to Florida law, local and state agencies need a judge's approval to use GPS tracking. But the standard they have to meet isn't as high as the standard for obtaining a search warrant.

To search someone's home or business, officers must have a reasonable belief that the person committed a crime.

To use GPS tracking, they simply must convince a judge that it's "relevant" to their investigation, said University of Florida law professor Michael L. Seigel.

"It's a much lower standard," he said. "It's not requiring them to show any suspicion about an individual's guilt."

There's also an easy way around state law. Local agencies could just ask the federal government for help. Federal agents don't need a warrant to use GPS tracking devices in Florida, Seigel said.

"Everybody's working in a joint task force these days," said Escobar. "They can ask the federal government to do things they can't do in the state system."

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Lottery winner Abraham Shakespeare had been missing for a year when Polk County detectives placed a GPS tracking device on a vehicle driven by DeeDee Moore for three days in January.

That's how they were able to retrace her steps and discover the $104.90 Walmart shopping trip, according to court records. Shakespeare's body was found four days later.

Moore was soon charged with shooting Shakespeare in April 2009, hiding his body and taking control of his millions. Now she sits in a Hillsborough jail, awaiting trial on a charge of first-degree murder.

It's unclear if a judge approved using GPS in this case. When asked if a judge signed off on it, the Hillsborough County State Attorney's Office and the Polk County Sheriff's Office both declined to comment.

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The Fourth Amendment of the U.S. Constitution protects against "unreasonable searches and seizures." But tracking someone in public spaces, the courts have ruled, doesn't constitute a "search."

There's nothing unreasonable about following someone on a public road or sidewalk. That's why officers don't need a warrant to physically surveil someone — or to use a GPS tracking device.

"We expect that other people will see us when we walk outside, our movements on the street are open to the public," said Stetson law professor Robert Batey. "It's not an intrusion upon a reasonable expectation of privacy for the police to tail someone."

But it is getting harder to tail someone, said Escobar.

"One of the problems they have is that the people they're tracking have become pretty savvy to these surveillance techniques," he said. "Even when you use multiple cars to track someone, it's a risk that you can be spotted.

"But with GPS tracking, there's no negative. You're going to be able to track that person and you can keep your distance."

Well, there's one negative: People are finding the devices.

In a recent case, a 20-year-old California student of Egyptian descent, Yasir Afifi, discovered a tracking device on his car when he took it for an oil change, according to Wired.com.

A friend posted pictures on the Internet, which led to a visit from FBI agents, who questioned Afifi and took the device back.

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Most federal and state courts have upheld the use of GPS tracking without a warrant. But some have dissented.

The U.S. District Court of Appeals for the D.C. Circuit ruled Aug. 6 that the government's warrantless, monthlong tracking of a suspected drug trafficker using GPS constituted an illegal search.

The judges said that "prolonged surveillance of a person's movements may reveal an intimate picture of his life." Constant surveillance could uncover criminal activity — but also reveal to the government that the subject is seeing a psychiatrist.

Days later, the 9th Circuit upheld the right of federal agents to plant a GPS tracking device on a suspected drug trafficker's vehicle without a warrant and to do so on a private driveway.

Those conflicting rulings mean the U.S. Supreme Court will likely decide the issue.

The real issue is resources, said University of Miami law professor Michael Froomkin. When the courts first gave the government the right to remotely track suspects, no one thought they'd one day have the money or technology to do so constantly.

"There was an unstated assumption behind a great deal of Fourth Amendment jurisprudence in our history that says surveillance is expensive and therefore has natural limits," he said. "That unstated assumption that people took for granted is no longer true."

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When Chief Judge Kozinski wrote his dissent in the 9th Circuit's ruling, GPS tracking wasn't his only concern. He wrote that there seems to be no limit to what technologies the government can use to violate privacy.

He noted that in 2009 a Sprint Nextel official revealed that the company gave its customers' cell phone locations to the government more than 8 million times that year. The company said that it was all done legally and that the number of customers affected was far less.

"By holding that this kind of surveillance doesn't impair an individual's reasonable expectation of privacy," wrote the judge, "the panel hands the government the power to track the movements of every one of us, every day of our lives. …

"There is something creepy and un-American about such clandestine and underhanded behavior."

Times researchers Shirl Kennedy and Carolyn Edds contributed to this report.